Graphite particles and lithium secondary battery using the same as negative electrode

• US 20010033822A1
• Filed: 04/03/2001
• Published: 10/25/2001
• Est. Priority Date: 08/08/1996
• Status: Active Grant

• Current Assignee: Atsushi Fujita, Kazuo Yamada, Tatsuya Nishida, Yoshito Ishii
• Original Assignee: Atsushi Fujita, Kazuo Yamada, Tatsuya Nishida, Yoshito Ishii
• Inventors: Nishida, Tatsuya, Ishii, Yoshito, Fujita, Atsushi, Yamada, Kazuo
• Granted Patent: US 6,447,956 B2
• Time in Patent Office: Days
• US Class Current: 423/448
• CPC Class Codes: C01B 32/20 Graphite
• CPC Class Codes: C01B 32/205 Preparation
• CPC Class Codes: C01P 2002/60 Compounds characterised by their crystallite size
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2004/54 Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension
• CPC Class Codes: C01P 2004/61 Micrometer sized, i.e. from 1-100 micrometer
• CPC Class Codes: C01P 2006/12 Surface area
• CPC Class Codes: C01P 2006/14 Pore volume
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/058 Construction or manufacture
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• CPC Class Codes: H01M 2004/027 Negative electrodes
• CPC Class Codes: H01M 4/0404 by coating on electrode collectors
• CPC Class Codes: H01M 4/0433 Molding
• CPC Class Codes: H01M 4/133 Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/1393 of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/583 Carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/587 for inserting or intercalating light metals
• CPC Class Codes: H01M 4/621 Binders
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y10T 29/49115 : including coating or impregnating
• CPC Class Codes: Y10T 428/2982 : Particulate matter [e.g., sphere, flake, etc.]

Abstract

A graphite particle obtained by assembling or binding together a plurality of flat-shaped particles so that the planes of orientation are not parallel to one another, or a graphite particle in which aspect ratio is 5 or less or specific surface area is 8 m²/g or less or the size of crystallite in the direction of c-axis of the crystal is 500 Å or more and the size of crystallite in the direction of plane is 1,000 Å or less as measured by X ray broad angle diffraction, or a graphite particle in which pore volume of the pores having a size falling in a range of 10² to 10⁶ Å is 0.4 to 2.0 cc/g per weight of graphite particle or pore volume of the pores having a size falling in a range of 1×10² to 2×10⁴ Å is 0.08 to 0.4 cc/g per weight of graphite particle is suitable for production of negative electrode of lithium secondary battery, and a lithium secondary battery obtained therefrom is excellent in rapid charge-discharge characteristics, cycle characteristics, etc.

Claims

1. A graphite particulate, wherein pore volume of pores having a size falling in a range of 1×

10² to 2×

10⁶ Å

is 0.08 to 0.4 cc/g per weight of the graphite particulate.

2. A graphite particulate according to

claim 1

, wherein said graphite particulate is obtained by assembling or binding together a plurality of flat-shaped particles so that the planes of orientation of the flat-shaped particles are not parallel to one another.

3. A graphite particulate according to

claim 1

, wherein said graphite particulate has an aspect ratio of 5 or less.

4. A graphite particulate according to

claim 1

, wherein said graphite particulate has a specific surface area of 8 m²/g or less.

5. A graphite particulate according to

claim 2

, wherein said graphite particulate has an aspect ratio of 5 or less.

6. A graphite particulate according to

claim 5

, wherein said graphite particulate has a specific surface area of 8 m²/g or less.

7. A graphite particulate according to

claim 1

, wherein said graphite particulate has an aspect ratio of 1.2 to 5.

8. A graphite particulate according to

claim 1

, wherein said graphite particulate has a specific surface area of 2 to 5 m²/g.

9. A process for producing the graphite particulate of

claim 1

, which comprises adding 1 to 50% by weight of a graphitizing catalyst to a raw material which can be graphitized, or of a graphite and a binder which can be graphitized, homogenizing the mixture and calcining the mixture, followed by pulverization.

10. A graphite paste comprising a graphite particulate of

claim 1

, an organic binder and a solvent.

11. A graphite paste according to

claim 10

, wherein said graphite particulate has an aspect ratio of 1.2 to 5.

12. A graphite paste according to

claim 10

, wherein said graphite particulate has a specific surface area of 2 to 5 m/g.

13. A negative electrode for lithium secondary battery, obtained by coating the graphite paste of

claim 10

on a current collector to prepare an integrated body.

14. A negative electrode according to

claim 13

, wherein said graphite paste contains graphite particulate having an aspect ratio of 1.2 to 5.

15. A negative electrode according to

claim 13

, wherein said graphite paste contains graphite particulate having a specific surface area of 2 to 5 m²/g.

16. A lithium secondary battery comprising a casing, a cover and at least one pair of negative and positive electrodes, said casing, cover and electrodes being disposed through intermediation of separators, and an electrolytic solution disposed in the surroundings thereof, wherein said negative electrode is the negative electrode of

claim 13

.

17. A lithium secondary battery according to

claim 16

, wherein said negative electrode includes a graphite particulate having pore volume, of pores with a size falling in the range of 102 to 106 Å

, of 0.4 to 2.0 cc/g per weight of the graphite particulate.

18. A lithium secondary battery according to

claim 17

, wherein said graphite particulate has an aspect ratio of 1.2 to 5.

19. A lithium secondary battery according to

claim 17

, wherein said graphite particulate has a specific surface area of 2 to 5 m²/g.